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Another method is to coagulate the blood, then remove the coagulated portion and use the residue for food purposes. This preparation, of course, contains no coagulable portions of blood, that is, the protein thereof known as fibrin. There is no reason for believing that preparations of blood will ever occupy any prominent position in the food supply, either of persons in health or of invalids.
Beef Tea. A very common food preparation from beef is that known as beef tea. In all essential particulars beef tea is nothing more than a rich unfiltered soup stock. Inasmuch, however, as it is constantly prescribed in many kinds of illness and is prepared under certain conditions it should be mentioned speci→ ally here in addition to the preparations already described. As in the case of meat juice, beef tea should always be prepared in the home, and immediately before using. It is a preparation which can not be properly made and kept without the addition of some preservative which renders it totally unfit for human consumption. The very choicest portion of the beef should be selected in the preparation of beef tea and it should be reduced to a fine state of comminution. The removal of the fat and tendons should be as complete as possible, as particularly the latter tend to add to the extract more of the gelatine-like principles than is desirable. The fragments should be mixed with a sufficient quantity of cold water to make the desired amount of beef tea, usually one pound of water to a pound of comminuted beef is a good proportion. The mixture should be kept cold for a considerable length of time with frequent stirrings in order to extract as much as possible of the nitrogenous. matter which becomes coagulated by heating. Salt may be used not only to promote the solubility but also to give the proper taste. After the lapse of an hour or more the vessel may be covered and gradually warmed. During this warming the mass should be frequently stirred so to as promote the solution. When finally the extraction is complete, before the tea is administered it should be cooked, that is, heated to the boiling-point, by which process the soluble protein is coagulated but not hardened, and the material is rendered more palatable. The beef tea should be administered without separating the coagulated fragments of albuminous material, which is in a state easily digestible, and adds much to the nutritive value of the mixture. Finally the residue of beef may be put into a bag and subjected to pressure to remove as much of the juice contained therein as possible. The difference between beef tea and soup stock, as will be seen, is largely in the filtering. The beef tea should retain the coagulated flocks, while in the soup stock they are removed. One pound of good lean beef and one pint of water yield about one-half pound of good beef tea. As in the case of soup stock, beef tea is not a very nutritive substance. It is, however, stimulating, and the nourishment which it contains is quickly absorbed. The soft, coagulated flocks of albumin are readily digested, and often a patient may be nourished for days on a preparation of this kind when he is in
a condition which renders it impracticable to use either solid or other liquid foods.
Beef tea is also made on a large commercial scale and with some degree of approximation to the home prepared article. For various reasons, however, which have already been advanced, a well made domestic beef tea which can be used as soon as prepared is to be preferred in all cases to the manufactured article. A beef tea properly made contains approximately the following composition:
Protein-soluble and flocculated,
DRIED AND POWDERED MEATS.
Dried and Powdered Meats.-The preparation of dried meat has already been described. There has lately been placed upon the market a number of preparations dried and finely ground, under various names, fanciful and those of the manufacturer. Inasmuch as ordinary meats are largely composed of water, it is evident that if the water can be removed without impairing the quality of the meat, great expense in transportation would be saved and the use of preservatives would be unnecessary. Various attempts, therefore, have been made to place dried meats upon the market. The meat powders are not only offered in their natural state of desiccation but also are prepared with a more or less previous digestion. One of the most common of these meat powders is known as somatose, which has been made in large quantities, and sold throughout all parts of the world. It consists largely of albumoses rather than of peptones, but this is true of a great many of the so-called peptone preparations." The composition of somatose is represented in the following table (Allen's Commercial Organic Analyses, Vol. IV, page 384):
The above data show that the meat still contains nearly 15 percent of moisture and that an alkali has been used to render the protein more soluble. This alkali has increased the quantity of mineral matter over that which would naturally be present. Whatever may be the relative value of the prepared protein matter as compared with that in the original meat, it is seen that a large quantity of it, practically as much as was in the original meat, has been preserved in the finished product. Whether or not it is advisable to use a preparation of this kind is a question to be left with the physician. It may be said unhesitatingly that in all cases of health somatose could not possibly present any
advantage over fresh meat. On the contrary, for theoretical and practical reasons, it is certain that it is less valuable.
Composition of the Ash of Meat Juice and Meat Broth.-The principal mineral component of the natural juice of meat broth or meat extract is phosphate of potassium, though there are also small quantities of magnesium and smaller quantities of calcium present. In addition to this there is a certain quantity of common salt present, which is determined, however, largely by the method of preparation. The following analysis shows the composition of the ash of a meat juice to which little or no common salt has been added:
Other constituents are not determined in this analysis. The phosphate of potassium may therefore be regarded as the principal natural ash constituent of meat extract and meat juice. (Zeitschrift für Biologie, Vol. XII, 1876.)
Adulteration of Meat Extract.-The principal adulterations of meat extract have already been mentioned. The substances used in preserving it are of the greatest hygienic consequence. These are chiefly salt and glycerol or alcohol. The use of all of these substances is reprehensible. Fortunately they are seldom used. Another adulteration which has been practiced is mixing the meat extract with extracts of yeast. The extract of yeast has valuable dietetic properties and contains the active principles of fermentation. It also resembles, in many respects, physically and chemically, the extract of meat, and can, therefore, be mixed with meat extract, and, being a cheaper article, forms a mixture which can be sold at a greater profit. The presence of yeast extract in meat extract can easily be determined by treatng the mixture with a strong solution of sulfate of zinc and filtering. In meat extract the filtrate obtained is always quite clear, but when a yeast extract is present the filtrate is turbid.
Active Principles Contained in Meat Extract.-Attention has already been called to some of the more important active principles, namely, meat bases which form a valuable portion of meat extract. There are various forms of nitrogenous bodies, however, besides meat bases, which become soluble naturally in meat or by the treatment of meat with digestive ferments. Lean meat, as is well known, consists almost exclusively of protein matter and water. This protein matter is principally insoluble. Under the action of digestive ferments the protein of meat becomes broken up into more soluble bodies, known as albumoses, proteoses and peptones,-the latter being the final product of solution. These bodies are still true protein bodies containing the elements of sulfur as one of their essential constituents. The meat bases, on
the contrary, contain the other elements that are in protein but do not have the sulfur element. They belong to that class of bodies which is known as simple amido compounds. All of these bodies are mixed together in meat juice or beef extract, and it is an important task of the chemist to separate them, both from an analytical point of view and the determination of their relative abundance. There is also another soluble or semisoluble protein substance in these extracts derived from the tendinous tissues and bones, namely, the gelatine or glue. This is quite a common product, being the soluble protein procured by the digestion of the tendons and bones. It is important, therefore, that the chemist should distinguish between the gelatine and the amido bodies. There is also a true and a false protein form of these soluble bodies, the true one being formed by natural proteolytic ferments and the false one being formed by heat or digestion under pressure of steam. The chemist should also be able to distinguish between the true extract formed directly from the meat and the yeast extract used as an adulteration.
It is not the purpose of this manual to enter into the details of how these different bodies may be distinguished from one another, as that is purely a chemical study. It is due, however, to the general reader that some explanation be given of the different classes of bodies which are contained in these extracts.
RELATION BETWEEN PRICE AND VALUE OF A NUTRITIVE EXTRACT.
Relation between the Price of an Extract and its Nutritive Value.The studies made in the Bureau of Chemistry show that there is little relation between the price of a beef extract and its real nutritive value. In three cases of extract which are all well known brands and are of the thick or pasty variety, showing that a dissolved meat had been added to them, the average weight of a package costing 45 cents was only 55 grams, or nearly a cent a gram. In another three samples of extract, also well known brands, of the same pasty variety and costing little more per package, it was found that the weight of the more expensive variety was double that of the first, costing only one-half cent per gram. In the case of the liquid extracts where no pasty material is incorporated there is still greater variation in the relation of the price to the nutritive constituents. An extract which retails for one dollar per bottle contains 91.69 percent of water and only .42 percent of nitrogen. Another so-called meat extract which retails at 60 cents per bottle must have been wholly an artificial product, since it contained no creatin or creatinin at all. It was also preserved by the addition of alcohol and contained an artificial coloring matter.
The ash existing in these extracts is, of course, usually due to the presence of large quantities of common salt. Sodium chlorid is added to this extract without any definite rule at all and sometimes in very excessive quantities. In some cases thirty percent of the total extract is composed of common salt. In other words, a person taking a solution of this kind would be injecting into his stomach a very concentrated brine. When common salt may
be sold at the rate of one dollar per pound, the profit on the transaction is one which ought to make the business exceedingly attractive.
The total phosphoric acid in the ash also shows variations, and if it were not so easy to add artificial phosphoric acid the actual amount present might be taken as a base by which quality could be judged. In the natural extract the total phosphoric acid should be in the proportion to organic phosphoric acid as Io to I, which is the natural condition in which it is found in meat extract. In many cases the amount of inorganic phosphorus is so great as to render it certain that a phosphate, probably the phosphate of soda, has been added. In another case the quantity of organic phosphoric acid was very much greater than could have possibly been the case in a natural product, indicating the addition of lecithin or glycerophosphoric acid. The amount of fat in beef extract, when properly prepared, should be very small and should certainly not exceed one percent, since by the proper method of preparation the fat is largely separated. In the pasty material, however, where the meat is reduced to a pulp and retained in the package the amount of fat will be very much greater.
The Nitrogenous Bases.-The average nitrogen content of the pasty or solid extracts varies from 6 to 9 percent. The nitrogen in the meat juice is subject to much greater fluctuation, depending largely on the content of solids. Although a high nitrogen content is not a guarantee of the character or mode of manufacture of an extract, it is naturally expected and is desirable.
The addition of gelatine to extracts is now largely practiced and has been for some years. By adding gelatine the manufacturer raises or maintains a certain. nitrogen content, but supplies the nitrogen in a form lacking in all quickly stimulating qualities, and the natural flavor of the meat extract nitrogen is lowered. The buyer is consequently deprived of the characteristic essentials of a beef extract although the nitrogen content is relatively high. In many cases only a small proportion of the original gelatine exists in the extract as such. The gelatine is converted by a gradual process of hydration into gelatoses and gelatine peptones. While the separation of gelatine from protein matter is a process in anything but a satisfactory condition, it is a far simpler process than the detection and separation of gelatoses and gelatine peptones from albuminoses and peptones. The question has not been thoroughly studied up to date.
The question of adulteration of meat extracts with gelatine is not the only form of adulteration we have to face. The mixing of varying amounts of yeast extract with meat extracts is being practiced at the present time in some countries. As we have not investigated this question, we cannot state whether it is practiced in this country at the present time or not.
Kinds of Preparations.-Meat preparations of the above types in general may be divided into three classes, liquid extracts, pasty extracts and powdered extracts. In addition to the above, within the last few years beef extract pellets, some of them being enclosed in gelatine capsules, have appeared